scholarly journals Evaluation of Soil Liquefaction in Harbor District in Tianjin City

2016 ◽  
Vol 10 (1) ◽  
pp. 293-300
Author(s):  
Gu Fei-hong
Keyword(s):  
Standard Penetration Test ◽  
Soil Liquefaction ◽  
Great Earthquake ◽  
Grain Composition ◽  
Related Data ◽  
Liquefaction Index ◽  
Liquefied Soils ◽  
Tianjin City ◽  
In Suit ◽  
Boundary Curves

The liquefaction of soils in the harbor district in Tianjin City near Tangshan, where a great earthquake occurred is a very important issue related to the soil’s compaction, grain composition and content of clay particle. This problem has not been fully considered due to the complexity and uncertainty of the soil properties data, since none of the previous investigations has been concerned about the liquefaction characteristics of this new harbor district. The evaluation of soil liquefaction has been made based on related data of the standard penetration test (SPT) from 26 investigation bore holes and 105 sieving tests. The results show that the liquefaction index of silt sand gradually decreases with the increase of the buried depth; soils less than 10.6 m in depth are of bad gradation identically. Soil less than 10.6 m in depth can be defined as liquefied soil which is further verified by sieving tests. Both the buried depth and particle grading have primarily significant influences on silt sands’ liquefaction. The results from sieve tests based on liquefied soils were found to fit well with the Tsuchida curves. It is believed that even without the in-suit SPT tests, Tsuchida boundary curves can be directly utilized to judge the liquefaction of soils in the harbor district.

scholarly journals Effect of Micropiles on Clean Sand Liquefaction Risk Based on CPT and SPT

2020 ◽  
Vol 10 (9) ◽  
pp. 3111 ◽  
Author(s):  
Visar Farhangi ◽  
Moses Karakouzian ◽  
Marten Geertsema
Keyword(s):  
Soil Properties ◽  
Factor Of Safety ◽  
Standard Penetration Test ◽  
Strength Properties ◽  
Soil Liquefaction ◽  
Penetration Test ◽  
Sand Liquefaction ◽  
Abrupt Decrease ◽  
Novel Approach ◽  
Jet Grouting

Liquefaction is a hazardous seismic-based phenomenon, which causes an abrupt decrease in soil strength properties and can result in the massive destruction of the built environment. This research presents a novel approach to reduce the risk of soil liquefaction using jet-grouted micropiles in clean sands. The saturated soil profile of the study project mainly contains clean sands, which are suitable to more reliably employ simplified soil liquefaction analyses. The grouting is conducted using 420 micropiles to increase the existing soil properties. The effect of jet grouting on reducing the potential of liquefaction is assessed using the results of the cone penetration test (CPT) and the standard penetration test (SPT), which were conducted before and after jet grouting by implementing micropiles in the project sites. According to three CPT-based liquefaction analyses, the Juang method predicts the most effective improvement range of the factor of safety in the clean sand. The Boulanger and Idriss, and Eurocode methods show comparable evaluations. Results of the SPT-based analyses show the most considerable increase of the factor of safety following the Boulanger and Idriss, and NCEER approaches in the SP soil. CPT- and SPT-based analyses confirm the effectiveness of jet grouting by micropiles on enhancing soil properties and reducing the risk of liquefaction.

Liquefaction at Strong Motion Stations and in Urayasu City during the 2011 Tohoku-Oki Earthquake

2013 ◽  
Vol 29 (1_suppl) ◽  
pp. 55-80 ◽  
Author(s):  
Brady R. Cox ◽  
Ross W. Boulanger ◽  
Kohji Tokimatsu ◽  
Clinton M. Wood ◽  
Akio Abe ◽  
...  
Keyword(s):  
Strong Motion ◽  
Standard Penetration Test ◽  
Soil Liquefaction ◽  
Case Histories ◽  
Cone Penetration ◽  
Penetration Testing ◽  
Cone Penetration Testing ◽  
Recent Sediments ◽  
Wave Methods ◽  
Strong Ground

The 2011 MW = 9.0 Tohoku-oki earthquake generated a large number of unique soil liquefaction case histories, including cases with strong ground motion recordings on liquefiable or potentially liquefiable soils. We have compiled a list of 22 strong motion stations (SMS) where surface evidence of liquefaction was observed and 16 SMS underlain by geologically recent sediments or fills where surface evidence of liquefaction was not observed. Pre-earthquake standard penetration test data and borehole shear wave velocity ( Vs) profiles are available for some stations, but critical information, such as grain size distribution and fines plasticity, are often lacking. In the heavily damaged city of Urayasu, we performed post-earthquake cone penetration testing at seven SMS and Vs profiles, using surface wave methods at 28 additional locations to supplement existing geotechnical data. We describe the liquefaction effects in Urayasu, the available site characterization data, and our initial data interpretations.

Probabilistic Assessment of Soil Liquefaction by Using Seismic Chinese Code

2012 ◽  
Vol 166-169 ◽  
pp. 2248-2252
Author(s):  
Sanguan Vongchavalitkul ◽  
Swein Kumpangta
Keyword(s):  
Safety Factor ◽  
Factor Of Safety ◽  
Standard Penetration Test ◽  
Soil Liquefaction ◽  
Probabilistic Assessment ◽  
Probability Method ◽  
Deterministic Method ◽  
Actual Measurement ◽  
First Order ◽  
First Order Second Moment

Deterministic safety factor are introduced by Z. CAO et al (2008) according to seismic Chinese code. The approach was deterministic method used the standard penetration test (SPT) to evaluate the liquefaction of soil. With this method, liquefaction of soil is predicted to occur if the factor of safety(FS), which in the ratio of critical SPT-N value(Resistance) over the actual measurement SPT-N(Load), is less than or equal to one. If the factor of safety greater than one, no soil liquefaction is predicted. Because the significant uncertainties in variable involved in the deterministic factor of safety, the probability method need to use. Probabilistic safety factor calculations provide a means of evaluating the combined effeces of uncertainties and provide a logical framework for choosing a factor of safety that is appropriate for the degree of uncertainty and consequences of failure. Then, a probabilistic assessment of soil liquefaction may be performed in which probability of failure and reliability index. By using the most widely reliability analysis as the First Order Second Moment (FOSM) method, the results of a probabilistic assessment of soil liquefaction can be used for engineering decision.

Regression model for evaluating liquefaction potential by discriminant analysis of the SPT N value

2005 ◽  
Vol 42 (3) ◽  
pp. 856-875 ◽  
Author(s):  
Sheng-Yao Lai ◽  
Ping-Sien Lin ◽  
Ming-Jyh Hsieh ◽  
Hoi-Fung Jim
Keyword(s):  
Discriminant Analysis ◽  
Standard Penetration Test ◽  
Cyclic Stress ◽  
Soil Liquefaction ◽  
Liquefaction Resistance ◽  
Multivariate Statistical ◽  
Liquefaction Potential ◽  
Cyclic Stress Ratio ◽  
N Value ◽  
Spt N Value

Discriminant models are developed for evaluating soil liquefaction potential, using standard penetration test (SPT) data for 592 occurrences of liquefaction and nonliquefaction. The discriminant model used is a multivariate statistical method. The square root of the SPT N value, (N1)601/2, and the logarithm of the cyclic stress ratio, ln CSR7.5, are adopted as the major parameters for analyses. Two models measuring liquefaction resistance through the SPT N value are also established in this study, which allows calculated results to be compared with the empirical curves. Key words: liquefaction, discriminant analysis, misclassified probability.

scholarly journals LPI Based Earthquake Induced Soil Liquefaction Susceptibility Assessment at Probashi Palli Abasan Project Area, Tongi, Gazipur, Bangladesh

2018 ◽  
Vol 10 (2) ◽  
pp. 105-116
Author(s):  
A. H. Farazi ◽  
N. Ferdous ◽  
A. S. M. M. Kamal
Keyword(s):  
Threshold Value ◽  
Flood Plain ◽  
Standard Penetration Test ◽  
Soil Liquefaction ◽  
Cumulative Frequency ◽  
Liquefaction Potential ◽  
Project Area ◽  
Potential Index ◽  
Liquefaction Hazard ◽  
Simplified Procedure

This study aims at evaluation of seismic soil liquefaction hazard potential at Probashi Palli Abasan Project area of Tongi, Gazipur, exploiting standard penetration test (SPT) data of 15 boreholes, following Simplified Procedure. Liquefaction potential index (LPI) of each borehole was determined and then cumulative frequency distribution of clustered LPI values of each surface geology unit was determined assuming cumulative frequency at LPI = 5 as the threshold value for liquefaction initiation. By means of geotechnical investigation two surface geological units—Holocene flood plain deposits, and Pleistocene terrace deposits were identified in the study area. We predicted that 14% and 24% area of zones topped by Pleistocene terrace deposits and zones topped by Holocene flood plain deposits, respectively, would exhibit surface manifestation of liquefaction as a result of 7 magnitude earthquake. The engendered hazard map also depicts site specific liquefaction intensity through LPI values of respective boreholes, and color index, which was delineated by mapping with ArcGIS software. Very low to low, and low to high liquefaction potential, respectively, was found in the areas covered by Pleistocene terrace deposits and Holocene flood plain deposits. LPI values of both units are such that sand boils could be generated where LPI > 5.

Reconsideration of case histories for estimating undrained shear strength in sandy soils

1999 ◽  
Vol 36 (5) ◽  
pp. 907-933 ◽  
Author(s):  
C E (Fear) Wride ◽  
E C McRoberts ◽  
P K Robertson
Keyword(s):  
Shear Strength ◽  
Sandy Soils ◽  
Standard Penetration Test ◽  
Undrained Shear Strength ◽  
Soil Liquefaction ◽  
Penetration Test ◽  
Case Histories ◽  
Original Case ◽  
Undrained Strength ◽  
Undrained Shear

When sandy soils respond in a strain-softening manner to undrained loading, an estimation of the resulting undrained shear strength (Su) is required to determine the potential for flow liquefaction at a given site. One of the most commonly used methods for estimating the undrained strength of liquefied sand is an empirical standard penetration test (SPT) based chart (originally proposed by H.B. Seed), which was developed using a number of case histories. The original interpretations of these case histories are viewed by many workers and regulatory agencies as the most authoritative measure of the liquefied strength of sand. Consequently, in comparison, other less conservative methods are generally held in an unfavourable light. This paper reexamines the original database of case histories in view of some more recent concepts regarding soil liquefaction. The objectives of this paper are to explore and reassess the issues involved in the original assessment and to offer alternative views of the case records. The conclusions presented here indicate that alternative explanations of the liquefied strength of sand are not inconsistent with the original case histories. Key words: sandy soils, soil liquefaction, undrained strength, standard penetration test (SPT).

scholarly journals Soil liquefaction potential in Eskişehir, NW Turkey

2011 ◽  
Vol 11 (4) ◽  
pp. 1071-1082 ◽  
Author(s):  
H. Tosun ◽  
E. Seyrek ◽  
A. Orhan ◽  
H. Savaş ◽  
M. Türköz
Keyword(s):  
Ground Water ◽  
Management Practices ◽  
Alluvial Soil ◽  
Experimental Studies ◽  
Standard Penetration Test ◽  
Soil Liquefaction ◽  
Water Levels ◽  
Liquefaction Potential ◽  
Geotechnical Investigations ◽  
Nw Turkey

Abstract. Liquefaction is one of the critical problems in geotechnical engineering. High ground water levels and alluvial soils have a high potential risk for damage due to liquefaction, especially in seismically active regions. Eskişehir urban area, studied in this article, is situated within the second degree earthquake region on the seismic hazard zonation map of Turkey and is surrounded by Eskişehir, North Anatolian, Kütahya and Simav Fault Zones. Geotechnical investigations are carried out in two stages: field and laboratory. In the first stage, 232 boreholes in different locations were drilled and Standard Penetration Test (SPT) was performed. Test pits at 106 different locations were also excavated to support geotechnical data obtained from field tests. In the second stage, experimental studies were performed to determine the Atterberg limits and physical properties of soils. Liquefaction potential was investigated by a simplified method based on SPT. A scenario earthquake of magnitude M=6.4, produced by Eskişehir Fault Zone, was used in the calculations. Analyses were carried out for PGA levels at 0.19, 0.30 and 0.47 g. The results of the analyses indicate that presence of high ground water level and alluvial soil increase the liquefaction potential with the seismic features of the region. Following the analyses, liquefaction potential maps were produced for different depth intervals and can be used effectively for development plans and risk management practices in Eskişehir.

scholarly journals Pseudo-static analysis of piles subjected to lateral spreading

2009 ◽  
Vol 42 (1) ◽  
pp. 28-38 ◽  
Author(s):  
Misko Cubrinovski ◽  
Kenji Ishihara ◽  
Harry Poulos
Keyword(s):  
Static Analysis ◽  
Ground Deformation ◽  
Ground Surface ◽  
Lateral Spreading ◽  
Soil Liquefaction ◽  
Pile Groups ◽  
Ground Shaking ◽  
Practical Procedure ◽  
Simplified Analysis ◽  
Liquefied Soils

Soil liquefaction during strong ground shaking results in almost a complete loss of strength and stiffness in the liquefied soil, and consequent large ground deformation. Characteristics of the liquefied soils and loads on piles are significantly different during the cyclic phase and in the subsequent lateral spreading phase. Thus, it is necessary to separately consider these two phases in the simplified analysis of piles. This paper describes a practical procedure for preliminary assessment of piles subjected to lateral spreading. Effects of a crust of non-liquefied soil at the ground surface, properties of liquefied soils and pile groups are discussed in relation to their modelling in the simplified pseudo-static analysis approach. Particular attention is given to the treatment of unknowns and uncertainties involved in the simplified analysis and the need for parametric studies.

The Effects of Vertical Stress on the Liquefaction Potential Originated from Buildings in The Urban Areas

2020 ◽  
pp. 351-372
Author(s):  
Mehmet Ozcelik
Keyword(s):  
Urban Areas ◽  
Sandy Soils ◽  
Standard Penetration Test ◽  
Soil Liquefaction ◽  
Vertical Stress ◽  
Limited Information ◽  
Liquefaction Potential ◽  
Empirical Procedure ◽  
Seismic Forces

Main purpose of this paper is to study the influence of vertical stress on soil liquefaction in urban areas. The literature provides limited information on vertical stress analysis of multiple footings, and, as a result, there is no accurate way to account for the effect of the foundation depth on liquefaction. Additionally, practical methods do not exist for considering the interaction between the neighboring foundations vertical stress and seismic forces in the urban area. Vertical stress distribution was calculated in examining the soil liquefaction potential exhibited by building foundations as a case study. The vertical stresses were chosen randomly for some buildings with foundation depths of 3.00 m; 4.50 and 6.00 m at the Burkent site (Burdur-Turkey). The influence of 5-storey buildings on the liquefaction potential of sandy soils was evaluated in terms of the safety factor (FS) against liquefaction along soil profile depths for different earthquakes. Standard Penetration Test (SPT) results were used based on simplified empirical procedure.

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